Hmm. I think the Puni Ana DX is probably a good choice. There's another website that rates onaholes called Onahodouga, and they have reviews for Puni Ana DX (http://onahodouga.com/archives/54322388.html
) and REAL (http://onahodouga.com/archives/54654866.html
). Both are rated four stars, so I think they're both probably pretty good. In fact, the same manufacturer (EXE) makes both of them. So I think between those two, it's up to personal preference.
I haven't been able to find any information on the other two, so I would say they're more risky. The third one is a parody onahole (of Puella Magi Madoka Magica), and parody onaholes are often not very good, so it seems like it might not be great. The Puritto Hip onahole seems like it could be mediocre as well.